The present disclosure relates to oil and gas exploration and production, and more particularly, to a packing element with a setting sequence that is used in a wellbore.
Wells are drilled at various depths to access and produce oil, gas, minerals, and other naturally-occurring deposits from subterranean geological formations. In the course of drilling and using a subterranean wellbore for hydrocarbon production, one or more packers, which may also be called packing elements, may be installed in the wellbore.
Packers are used in wells to seal off annular spaces between tubular strings (such as tubing and casing or liner strings, etc.) or between a tubular string and a wellbore surface. Another use for some packers is to support tubing and other equipment while also providing the seal in a well annulus between, for example, the tubular string and the wellbore surface. In wells with multiple reservoir zones, packers may be used to isolate perforations for each zone. Packers may also be used to protect the casing from pressure and produced fluids, isolate sections of corroded casing, casing leaks, or squeezed perforations, and isolate or temporarily abandon producing zones.
Based on their primary use, packers may be divided into two main categories: production packers and service packers. Production packers are those that remain in the well during well production. Service packers are used temporarily during well service activities such as cement squeezing, acidizing, fracturing, and well testing. Packers may also be classified according to whether they are permanent or retrievable. A permanent packer is removed using milling in order to break and remove the permanent packer from within the wellbore. The main advantages of permanent packers are potentially lower cost and greater sealing and gripping capabilities. A retrievable packer may be unset and removed by, for example, either shearing a metal ring or shifting a sleeve to disengage connecting components of the retrievable packer.
Retrievable packers may have a complicated design and generally lower sealing and gripping capabilities, but after removal and subsequent servicing, they may be reused.
Packers are set by providing a compressive force across the packer. For example, certain packers are set hydraulically, other packers are set using a differential fluid pressure across the packer, and still other packers are set mechanically. One limiting factor associated with packers is sealability or pressure integrity of the packer which can be affected by how the packer is set initially as well as other variables including, but not limited to, a packer shape and material.
The illustrated figures are only exemplary and are not intended to assert or imply any limitation with regard to the environment, architecture, design, or process in which different embodiments may be implemented.